I think the hero weapons can be used with all classes, not only with the main.
for example im adventurer hero and i can only use the dagger with this class, i think this would be change.
Hero weapons are boosted and to give ability to use on any subclass is huge advantage.
I agree that for certain classes hero weapons are quite useless like for daggers and healers.
That's why for Infinity Stinger blow skill success chance is increased and probably I will do something for healers too but I'm not sure what at the moment.